In a world of questionable claims and dubious pseudoscience about how to live a long and productive life, this book stands out. The author defines a "Blue Zone" as an area where there is an unusually high number of people living a century or more. Furthermore, they are people who have remained mentally and physically vibrant as they aged. Four areas are identified and examined:
*) In the Barbagia region of the Italian island of Sardinia in the Mediterranean Sea. In one village of 2,500 there were seven people 100 years or older.
*) The Japanese islands of Okinawa, site of one of the bloodiest battles in World War II.
*) Loma Linda, California where the people who make it a Blue Zone are Seventh Day Adventists.
*) An area of Costa Rica in Central America.
As a mathematician/statistician, my first thought was that this would turn out to be another false claim. I based this on two natural premises.
*) While modern records are complete, the birth records of these people would extend back to the start of the twentieth century, a time when the recording of births was much less precise. Therefore, some of the claims of advanced age could be false.
*) Given the large number of potential Blue Zones that could be created, the four cited in the book could just be statistical anomalies that can be expected due to the workings of chance. Those anomalies could also be due to the concentration of the members of a single family whose genetic makeup strongly favors long life.
The meticulous scholarship of various people, which includes the author, renders the first objection untenable. By examining the records in detail, there is no doubt that the ages of the people are accurate and the Blue Zones do exist.
The second objection is much harder to refute. The world is a big place and slight modifications of the borders can turn something that is close to a Blue Zone into something that is. Certain families have the genes for longevity, for example the people in one line of my wife's family routinely live into their nineties. Given the numbers of the Barbagia region, the presence of one or two such families could be enough to create a Blue Zone. While this would not change the fact that the data is interesting, a genetic anomaly would render any lifestyle conclusions moot for everyone else lacking the appropriate genetic components.
In carrying out a comparison of the lifestyles of the people in the Blue Zones around the world, some common factors clearly emerge.
*) They all have a strong and supportive social structure. All remain active in their community, they are surrounded by people who care about them and that they care about.
*) The centenarians have worked at heavy physical labor their entire lives and most still do. While they do eat meat, it is not a daily component of their diets.
*) The centenarians tend to have a lower level of stress in their lives and the hard work tends to help them burn off what stress they have.
These factors are not news to anyone who pays attention to the elements of a healthy lifestyle. Therefore, there is no reason to suspect an unusual environmental factor being a cause of the Blue Zone. Eat healthy, avoiding stress and exercise are the three key ingredients to a long and healthy life and that is true inside and outside the Blue Zones.
This book is a welcome and refreshing contribution to the literature about living longer. Although it is readable in nature and tone, it is scholarly enough to pass all tests of dubious credibility.
